Process for manufacturing color-screens.



CARL sPATH, F s'rneL IKEAR'BEQLIN COMPANY, or noonns'rnn,

raocnss ron iitifn No Drawing.

Specification (ifjIie tters latent.

Y,"ASSIGNOR TO EASTMAN KODAK oi airIn ;'jfconroruzvrron on NEW YORK.

cant tine COLOR-SCREENS.

Patented July 29, 1 913.

. A ueafion'mtimmh 24,1913. Serial No. 756,460.

To all whom it may concern f I Be it known that; I,-CARI. SPKTH, ofSteglitz, near Berlin, Empire of Germany, have invented certain new. anduseful jImprovements in Prfocesses for Manufacturing Color-Screens; andI do hereby declare thev following to'be 'a full, clear, and exact'descript-ion'of the same. I I

My invention has for its object to improve theconstruction. of screensused in photography, and particularly polychrome color screens used inso called color photog- I raphy, said screens consisting of atransparent sheet of Converted cellulose, andparticularly,nitro-cellulose, having fine lines, dot-s or-areas stained indifferentcolors, and I it'consists generally in staining or dyeing atleast one class of the areas in such manner that the color Wlll. neitherfadenor be (11$ char I the film may be subjected.

or sheet of converted cellulose as 'nitro celg lulose so as torender-these portions'capable preferably containing a colloid, Such ,as

gum arabic, glue or gelatin, and tllenjxtanf;

ning or hardening the colloid so a's to-render the production of colorscreens 'inwhich-lab ter the stained areas are very minute, I

prefer to use in all instances stains o'r-dyesf in aqueous solutions, asthese are less liable to be affected by light or to fade.

In carrying out my invention the sheetof converted cellulose, preferablynitro-cellulose, orisuchportions thereof as are to'be dyed or stained,are treated in a bath of a mixture of alcohol and acetone. theproportion-of these materials being dependent in some degree upon thecomposition and quality of; the converted cellulose used which caneasily-be determined by preliminary tests. Ithasfbeen found that theroportions of the quantity of the alcoho -acetone bath varyf betweeneighty per cent. alcohol to twentyper cent; acetone and ninety-four percent. alcohol to six per cent. acetone. The alcohol-acetone bath inwhich the sheet remains for from. "thirty seconds to two -minutes,dependent-"also upon the composition and qualityof thelsheet, serves toopen acid.

ged by any of the processes to whichthesurface of the unprotectedportion or renders it capable of absorbing water for a brief length oftime, and the sheet is then treated for a half a minute in pure water,and then it is dipped or treated for about one minute in a four percent. aqueous solution of a dye, such as chinolin yellow to which hasbeen added twenty-five per cent. of a solution of five per cent. gumarabic or .gelatin' and then is tanned for about five minutes in a tenpercent. solution of tannic A cellulose sheet, or parts thereof whichare dyed and tanned in such a way is not affected by any subsequentbaths and in consequence cannot be redyed.

As a practical manner of utilizing the process above described in themanufacture .of polychrome screens containing lines, dots or-difierentlycolored areas for use in color photography, I proceed as follows: I takeV i a sheet or film of Intro-cellulose and print a Briefly stated, hemventlonconsists-in opening or treating the portions ofjthe-jfil'tn.series of fin'e lines thereon in resist ink of a resinousor -fattynature and 'then immerse "thesheetin a preparatory or softening bathcontai ningfrom to partsacetone to 95 of receiving a dye in anaqueoussolution" to 80 partsiof grain alcohol,'the proportions depending-uponthe age of the sheet and ';:quality of the cotton from which it is I I Iformed, more acetone being required as the [the same insoluble andunaifectedlby'lighflK The process, generally speaking, may been? pliedto larger areas than arerequired-51infilm surface is harder. Afterremoval from the bath'the surface of the sheet is Washedwith water andthen is allowed to. dry very slightly and. then ispassed into an aqueoussolution of a red dye also containing a small percentage (about 20%) ofa 5% solution of acolloid as gelatin and a little alcohol.

This dye stains the parts unprotected by the resist, and the sheet ispassed through. a solution oftannic acid or similar material to tan orrender the colloid insoluble. The surplus dye is then washed from thesurface and the resist removed by benzol or other solvent. I then printlines in the resist ink diametrically across the red stained lines inthe sheet, stainthe unprotected portions of the cellulose with a bluedye in either an alcoholic or aqueous solution which will not affect thered lines, then remove the resist lines and dye the remaining portionsof the film with a green dye of such nature that it will not affect thepreviously dyed surface.

I claim as my invention:

1. The process of making photographic screens having a convertedcellulose base 7 consisting in placing lines of resist upon a convertedcellulose sheet, subjectin the surface of the sheet to the action of aath containing acetone and alcohol, then subjecting the sheet surface tothe action of a dye in an aqueous solution containing a small quantityof a colloid and then to the action 'of a tanning solution.

2. The process of making color screens consisting in treatingpredetermined portions of the surface of a nitro-cellulose sheet bysubjecting them to the action of a partial solvent of thenitro-cellulose, staining or dyeing the parts so treated with an aqueousdye containing a colloid and then tanning the colloid and thereby fixingthe dye in such portions.

3. The process of making polychrome photographic screens consisting incovering certain portions of a sheet of nitro-cellulose with a resist,subjecting the unprotected surface of the sheet to the action of a bathcontainin acetone and alcohol, then subject-ing said parts to the actionof an aqueous dye containing a c'olloid, then applying a tanningsolution, then washing the surface with water, then partially drying thesurface, then removing the resist and applying a resist topa'rts only ofthe surface protected by the first resist, then dyeing the exposedsurface, then removing the resist and 1 finally subjecting the remainingsurface of the sheet to the action of a dye solution which will notinjuriously affect the dye last previously applied.

' CARL SPATH. Witnesses: I

J OSEPH Nnum'innnn, Josnr P. WILDEGGEE.

